Primer



Dec. 20, 1966 H. STADLER ETAL PRIMER Filed Dec. 4, l964 FIG! HGZb

INVENTORS HANS STADLER HEINZ GAWLICK BY Ema, ATTORNEY United States Patent "ice 3,292,540 PRIMER Hans Stadler, Nurnherg, and Heinz Gawlick, Furth, Bavaria, Germany, assignors to Dynamit Nobel Aktiengesellschaft, Troisdorf, Germany Filed Dec. 4, 1964, Ser. No. 416,029 Claims priority, application Germany, Dec. 6, 1963,

17 Claims. or. 102-45 The present invention relates to a percussion primer, and more particularly to a primer anvil construction for use with high-sensitivity primers.

With percussion primers a so-called primer anvil is used in general as counter-surface or abutment against the impact exerted by the firing pin, against which is pressed the primer composition of the primer or percussion cap. The sensitivity of the primer depends on the surface pressure produced by the impact between the anvil and the primer composition. The smaller the surface pressure, the smaller the sensitivity of the percussion primer. Since one aims in general at a high sensitivity, various possibilities have already been developed in order to increase the surface pressure by decreasing the anvil surface. Thus, for instance, it has already been proposed heretofore to construct with an anvil having a central ignition channel, the impact edge as a ring with sharp edges. This undoubtedly produces an increase in the sensitivity as compared to an anvil with a closed surface, however, in many cases this does not suflice. An anvil has also been proposed already which terminates in a sort of a point, that is, in a very small impact surface. The surface pressure becomes very high as a result of such an arrangement, but a difficulty arises with this construction and also with the other aforementioned constructions which could not be obviated heretofore with sufiicient certainty.

The safety of the ignition or priming depends, in fact, not from the impact surface of the anvil but also on the fact, how the firing pin or striker impinges against the impact surface. With high precision devices, which can be manufactured with a corresponding high accuracy, one figures that the center point of the firing pin abutment does not deviate more than 0.5 mm. from the center point of the anvil. When these small tolerances are maintained, substantial difficulties need not be feared. However, numerous applications of percussion primers also exist in which such a high precision and accuracy in the location of the firing pin with respect to the anvil is not obtainable. If the firing pin impinges with a larger eccentricity, then the impact effect on the anvil is correspondingly decreased. Heretofore, one has had recourse in such cases to increasing the anvil surface by the extent of the eccentricity of the firing pin to be expected, however, one had to accept in that case a corresponding reduction in the sensitivity to percussion or impact.

The present invention aims at producing a primer anvil which assures also with relatively large eccentricity of the firing pin a high surface pressure, that is, a high sensitivity. This aim is achieved by the present invention in that the anvil is constructed in plate form with a plurality of impact humps or ridges of small surface at the impact edge. The term humps is to be interpreted in this context to mean both ledge or bar-like projections as well as point-like projections.

It is possible by the use of the present invention to produce a relatively large impact surface at the anvil which, however, does not become effective in its entirety but only in the humps thereof. Consequently, even if the firing pin impinges with relatively large eccentricity with respect to the anvil axis, a high surface pressure will always be produced which imparts to the primer the required sensitivity.

3,292,546 Patented Dec. 20, 1966 The projected surface of the impact edge is selected in particular so large that it is approximately equal to the thickness of the plate. A square impact surface results in this manner of such extent that it equalizes the possible eccentricities of the firing in all directions.

If the humps are constructed as impact ledges or strips, then they should in particular have a spacing of about half the diameter of the firing pin.

In an actual test utilizing the present invention, which has proved very successful, the anvil was stamped out of sheet metal of 1.4 mm. thickness with impact ledges whose distance amounted to 0.8 mm.

Accordingly, it is an object of the present invention to provide an anvil for percussion primers which obviates, by simple means, the shortcomings and drawbacks encountered with the prior art constructions.

Another object of the present invention resides in the provision of a primer anvil which assure high sensitivity even in case of eccentric impact of the firing pin.

A further object of the present invention resides in the provision of a primer anvil construction which can be made in a simple manner without requiring high tolerances in its dimensions or the dimensions of the firing pin mechanism.

Another object of the present invention resides in the provision of a primer anvil, which is so constructed and arranged as to assure a high percussion etfect even in case of eccentric impact of the firing pin.

A further object of the present invention resides in the provision of a primer anvil achieving the aforementioned aims and objects by extremely simple means in such a manner as to safeguard also a high sensitivity owing to a high surface pressure.

These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing, which shows, for purposes of illustration only, two embodiments in accordance with the present invention, and wherein:

FIGURE 1 is a cross sectional view through a primer with a primer anvil in accordance with the present invention having two impact ledges and assembled into a primer,

FIGURE 2 is an elevational view of a modified embodiment of a primer anvil with three impact ledges in accordance with the present invention,

FIGURE 2a is a plan view on the primer anvil of FIGURE 2, and

FIGURE 2b is a right side elevational view of the primer anvil of FIGURE 2.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to FIGURE 1, the primer anvil is generally designated in this figure by reference numeral 1 and has a construction in accordance with the present invention. More particularly, the primer anvil 1 has the shape of a plate which converges comically in the lower part 2 thereof. The impact edge is recessed at 3 so that two impact ledges 4 and 5 of small surface result. The impact ledges 4 and 5 abut against the cover 7 of the primer composition 8 which is pressed into a blank or cup 9.

The anvil 1 and the cup 9 are inserted into a case 12. Two shoulders 10 and 11 are formed into the anvil 1, whose diameter is approximately equal to the inner diameter of the case 12.

The anvil 1 is supported with the shoulders 10 and 11 thereof against a case 13 which is inserted into the case 12 and is held therein by a flanged rim 15. The case 13 serves for the accommodation of a booster charge 14 which is also contained in the cup 9. The booster charge 14 is closed off in the upward direction by a foil 22.

If with the new construction of the anvil 1 according to the present invention the firing pin (not shown) impinges eccentrically against the impact surface 16 of the case 12, then in any case one of the two impact ledges 4 or 5 becomes fully efiective, that is, the sensitivity of the primer is also high with eccentric impacts.

If one desires to achieve .a still higher sensitivity, then one can increase the number of the impact ledges. FIG- URE 2 illustrates an example of such modification. The impact edge of the anvil 1 is twice undercut at 17 and 18 so that three impact ledges 19, 20, and 21 result.

FIGURE 2b shows the diameter of the projection surface of the impact edge. This diameter fis substantially equal to the thickness d of the anvil 1 so that the impact surface between the two outer ledges 19 and 21 is a square. The distance of the impact ledges is thereby equal to half the firing pin diameter. Even with very large eccentricity of the firing pin a high sensitivity of the primer is assured thereby.

While we have shown and described two embodiments in accordance with the present invention, it' is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. A primer anvil for percussion primers comprising a plate member having impact edge means, and said impact edge means being provided with a plurality of impact hump means, each having a relatively small impact effective surface of substantial extent,

a tubular case member, said plate member being partially inserted into said tubular case member and being provided with lateral shoulder projections axially abutting against the end of said tubular case member that is closest to said impact edge means,

a booster charge within said tubular case member.

2. A primer anvil for percussion primers comprising a plate member having impact edge means, and said impact edge means being provided with a plurality of impact hump means, each having a relatively small impact elfective surfac of substantial extent,

a tubular case member, said plate member being partially inserted into said tubular case member and being provided with lateral shoulder projections axially abutting against the end of said tubular case member that is closest to said impact edge means,

and an outer case closed at the bottom thereof, said tubular case member together with the plate member being inserted into said case, and a cup-shaped primer cup supported against the bottom of the said outer case.

3. A primer anvil for percussion primers comprising a plate member having impact edge means, and said impact edge means being provided with a plurality of impact hump means, each having a relatively small impact effective surface of substantial extent,

a tubular case member, said plate member being partially inserted into said tubular case member and being provided with lateral shoulder projections axially abutting against the end of said tubular case member that is closest to said impact edge means,

a booster charge within said tubular case member,

and an outer case closed at the bottom thereof, said tubular case member together with the plate member being inserted into said case, and a cup-shaped primer cup supported against the bottom of the said outer case.

4. A prime anvil for percussion primers comprising a plate member having lateral edges and impact edge means, and said impact edge means being provided with a plurality of impact hump means, each having a relatively small impact effective surface of substantial extent,

said lateral edges converging in the direction toward the impact edge means and the impact edge means being undercut to thereby form the impact hump means,

a tubular case member, said plate member being partially inserted into said tubular case member and being provided with lateral shoulder projections axially abutting against the end of said tubular case member that is closest to said impact edge means,

a booster charge within said tubular case member,

and an outer case closed at the bottom thereof, said tubular case member together with the plate member being inserted into said case, and a cup-shaped primer cup supported against the bottom of the said outer case.

5. A primer anvil for percussion primers comprising a plate member having lateral edges and impact edge means, and said impact edge means being provided with a plurality of impact hump means, each having a relatively small impact effective surface of substantial extent, said lateral edges converging in the direction toward the impact edge means and the impact edge means being undercut to thereby form the impact hump means.

the projected surface of the impact edge means forming a substantially square surface,

.a tubular case member, said plate member being partially inserted into said tubular case member and being provided with lateral shoulder projections axially abutting against the end of said tubular case member that is closest to said impact edge means,

a booster charge within said tubular case member,

and an outer case closed at the bottom thereof, said tubular case member together with the plate member being inserted into said case, and a cup-shaped primer cup supported against the bottom of the said outer case.

6. A percussion primer, comprising a primer explosive charge; a primer anvil mounted closely adjacent to said charge; said anvil including .a substantially flat plate of rigid material having a predetermined thickness; said plate having generally parallel flat opposite faces and side edges extending generally at right angles to said faces; said plate having impact edge means abutting said charge for receiving the impact delivered to said charge by a firing pin; said edge means having one and only one channel extending from one of said faces to the other of said faces and at substantially right angles to said faces, and defining a single impact edge on each side of said channel extending from one of said faces to the other of said faces and at substantially right angles to said faces; the dimensions from one of said faces to the other of said faces of said ledges being substantially equal to the thickness from one of said faces to the other of said faces of said plate; and said edge means being substantially square in plane form.

7. The device of claim 6, including a substantially tubular outer case having a closed bottom end; a cup-shaped primer cup supported against the bottom of said outer case; said primer explosive charge being contained within said primer cup; a booster charge substantially surrounding said plate; and a cover mounted within said primer cup separating said primer explosive charge and said booster charge.

8. The device of claim 6, wherein said plate has opposite shoulder portions extending radially outwardly; a tubular case member; said plate being partially inserted into said tubular case member with said shoulders axially abutting against the end of said tubular case member that is closest to said impact edge means; an outer substantially tubular case being closed at the bottom; said tubular case member and said plate being completely mounted within said outer case; and said primer explosive charge being located between the bottom of said outer case and said edge means. 1

9. The device of claim 8, wherein said outer case has an upper open end with a flanged rim extending inwardly;

and a closure disc mounted between said flanged rim and said tubular case member for axially supporting said tubular case member and closing the upper end of said outer case.

10. The device of claim 9, including a booster charge located within said tubular case member and substantially surrounding said plate.

11. The device of claim 10, including a cup-shaped primer cup supported against the bottom of said outer case and containing said primer explosive charge; said booster charge extending into the upper open end of said primer cup; and a cover mounted within said primer cup separating said primer explosive charge and said booster.

12. A percussion primer, comprising a primer explosive charge; a primer anvil mounted closely adjacent to said charge; said anvil including a substantially flat plate of rigid material. having a predetermined thickness; said plate having generally parallel flat opposite faces and side edges extending generally at right angles to said faces; said plates having impact edge means abutting said charge for receiving the impact delivered to said charge by -a firing pin; said edge means having two and only two channels extending substantially parallel to each other from one of said faces to the other of said faces and at substantially right angles to said faces, and defining only three impact ledges, one of said ledges being on each side of said channels extending from one of said faces to the other of said faces and at substantially right angles to said faces; the dimension from one of said faces to the other of said faces of said ledges being substantially equal to the thickness from one of said faces to the other of said faces of said plate; and said edge means being substantially square in plane form.

13. The device of claim 12, including a substantially tubular outer case having a closed bottom end; a cupshaped primer cup supported against the bottom of said outer case; said primer explosive charge being contained within said primer cup; a booster charge substantially surrounding said plate; and a cover mounted within said primer cup separating said primer explosive charge and said booster charge.

14. The device of claim 12 wherein said plate has opposite shoulder portions extending radially outwardly; a tubular case member, said plate being partially inserted into said tubular case member with said shoulders axially abutting against the end of said tubular case member that is closest to said impact edge means; an outer substantially tubular case being closed at the bottom; said tubular case member and said plate being completely mounted within said outer case; and said primer explosive charge being located between the bottom of said outer case and said edge means.

15. The device of claim 14, wherein said outer case has an upper open end with a flanged rim extending inwardly; and a closure disc mounted between said flanged rim and said tubular case member for axially supporting said tubular case member and closing the upper end of said outer case.

16. The device of claim 15, including a booster charge 7 located within said tubular case member and substautially surrounding said plate.

17. The device of claim 16, including a cup-shaped primer cup supported against the bottom said outer case and containing said primer explosive charge; said booster charge extending into the upper open end of said primer cup; and a cover mounted within said primer cup separating said primer explosive charge and said booster.

References Cited by the Examiner UNITED STATES PATENTS SAMUEL FEINBERG, Primary Examiner.

BENJAMIN A. BORCHELT, Examiner.

R. F. STAHL, Assistant Examiner, 

6. A PERCUSSION PRIMER, COMPRISING A PRIMER EXPLOSIVE CHARGE; A PRIMER ANVIL MOUNTED CLOSELY ADJACENT TO SAID CHARGE; SAID ANVIL INCLUDING A SUBSTANTIALLY FLAT PLATE OF RIGID MATERIAL HAVING A PREDETERMINED THICKNESS; SAID PLATE HAVING GENERALLY PARALLEL FLAT OPPOSITE FACES AND SAID EDGES EXTENDING GENERALLY AT RIGHT ANGLES TO SAID FACES; SAID PLATE HAVING IMPACT EDGE MEANS ABUTTING SAID CHARGE FOR RECEIVING THE IMPACT DELIVERED TO SAID CHARGE BY A FIRING PIN; SAID EDGE MEANS HAVING ONE AND ONLY ONE CHANNEL EXTENDING FROM ONE OF SAID FACES TO THE OTHER OF SAID FACES AND AT SUBSTANTIALLY RIGHT ANGLES TO SAID FACES, AND DEFINING A SINGLE IMPACT EDGE ON EACH SIDE OF SAID CHANNEL EXTENDING FROM ONE OF SAID FACES TO THE OTHER OF SAID FACES AND AT SUBSTANTIALLY RIGHT ANGLES TO SAID FACES; THE DIMENSIONS FROM ONE OF SAID FACES TO THE OTHER OF SAID FACES OF SAID LEDGES BEING SUBSTANTIALLY EQUAL TO THE THICKNESS FROM ONE OF SAID FACES TO THE OTHER OF SAID FACES OF SAID PLATE; AND SAID EDGE MEANS BEING SUBSTANTIALLY SQUARE IN PLANE FORM. 